1. Field of the Invention
The present invention relates generally to method and apparatus for semiconductor processing, and more particularly to thermal exchanger assembly for a wafer chuck assembly.
2. Description of the Background Art
In semiconductor wafer processing, the wafer is conventionally maintained within a desired temperature range. Though this may involve regulating temperature in a process chamber, it conventionally involves controlling the temperature of the wafer.
Others have addressed wafer temperature control by providing chilled water through a wafer support pedestal. By cooling the wafer support pedestal, the wafer resting on a wafer chuck is cooled as well. However, this approach is time consuming, and conventionally response times are limited to approximately 2 minutes per degree. Because of the time required for chilled water to take effect, compensation times may be too long for rapid thermal processing or other processing causing rapid wafer temperature changes.
Others have suggested using thermo-electric devices. These devices are disposed under a support surface supporting the wafer in an oriented planar array. However, temperature gradients form between such thermo-electric devices and cause variation across the wafer. Additionally, a planar array of thermo-electric devices is limited to surface area under the support surface.
To address these limitations, others have suggested attaching at least one thermo-electric device to a stem, which is attached to a platen. However, stem length may be limited in some process chambers. Accordingly, it would be desirable to provide a solution having more available surface area within a confined volume for attaching at least one thermo-electric device.
An aspect of the present invention comprises a thermal exchanger assembly for a wafer chuck assembly. The thermal exchanger assembly comprises a first manifold having a first set of radially positioned fins, and a second manifold having a second set of radially positioned fins. The first and second set of radially positioned fins interleaved with one another to provide spaced-apart pairs of fins. At least one thermo-electric device is alternately located between and in thermal communication with the pairs of fins.
Another aspect of the present invention is a thermal exchanger assembly at least partially located in a process chamber of a processing system. These and other aspects of the present invention will be more apparent from the following description.